Type and Form


Washers can be categorised into three types;

  • Plain washers, which spread a load, and prevent damage to the surface being fixed, or provide some sort of insulation such as electrical
  • Spring washers, which have axial flexibility and are used to prevent fastening or loosening due to vibrations
  • Locking washers, which prevent fastening or loosening by preventing unscrewing rotation of the fastening device; locking washers are usually also spring washers.ter diameter (OD) about twice their inner diameter (ID), but this can vary quite widely.

Washers are usually metal or plastic. High-quality bolted joints require hardened steel washers to prevent the loss of pre-load due to Brinelling after the torque is applied.

Washer Types

  • Flat A flat washer, used to distribute load. Available in SAE, USS and other patterns.
  • Fender An oversize flat washer used to further distribute load especially on soft materials. 
  • Finishing A washer used to obtain a ‘finished’ look. Usually used with oval head screws.
  • Split Lock The most common style of washer used to prevent nuts and bolts from backing out .
  • External Tooth Lock A washer with external ‘teeth’. Used to prevent nuts and bolts from backing out.
  • Internal Tooth Lock A washer with internal ‘teeth’. Used to prevent nuts and bolts from backing out.
  •  Square A square shaped washer. 
  •  Dock Dock washers have a larger outside diameter and are thicker than standard. 

See More


If you've got a question, odds are we've got the answer